Device for overcoming dead-centers



' (No Model.)

D SEIBERT, Sr DEVICE FOR OVEROOMING DEAD, OENTERS.

Patented Aug. 6, 1895.

David Se 65 6777,37:

UNITED STATES PATENT OFFICE.

DAVID SEIBERT, S'R., OF PETOSKEY, MICHIGAN.

DEVICE FOR OVERCOMING DEAD-CENTERS.

SPECIFICATION forming part of Letters Patent N 0. 543,903, dated August 6, 1895.

Application filed April 20, 1894. Serial No. 508,312. (No model.)

To all whom it may concern:

Be it known that 1, DAVID SEIBERT, Sr., a citizen of the United States, residing at Petoskey, in the county of Emmet and State of Michigan, have invented a new and useful Device for Overcoming Dead-Centers in Crank Mechanisms, of which the following is a specification.

The invention relates to improvements in out in the claims hereto appended.

In the drawings, Figure l is a perspective view of a device for overcoming dead-centers constructed in accordance with this invention. Fig. 2 is a vertical sectional view of the same. Fig. 3 is an enlarged detail sectional view of the yielding connection between the vibrating spring and the pitman. Fig. 4 is a detail view of the lower end of the vibrating spring. I Like numerals of reference indicate corresponding parts in all the figures of the drawlngs.

1 designates a treadle mounted in. the usual manner on a horizontal rod or shaft 3 of the frame 2 of a sewing-machine. The treadle is provided with an arm 5 and is connected by a pitman 4 with a crank 5 of a horizontal shaft 6. The shaft 6 may be the drive-shaft of asewing or any other machine-such as a lathe or the like-but the device is especially adapted for use in connection with sewingmachines. A spring 10 extends upward from one end of the treadle, and its upper portion is located in front of the shaft 6 and extends above the same and is yieldingly connected with the pitman at its point of attachment to the crank 5 of the shaft 6, whereby the spring operates to carry the crank-shaft upward and forward past the dead-centers. The lower end of the spring is adj ustably connected with the treadle to vary its tension, and the spring is composed of a strip of resilient metal and upper and lower arms 11 and 7. The lower arm 7 is connected to an oblong frame which is rigidly mounted on the treadle and which has an upper bar 8 and a lower bar 20, provided at intervals with perforations. The lower end of the arm 7 is adjust-ably secured to the bar 20 by a pin arranged in one of the perforations thereof, and the upper portion of the arm 7 is secured to the bar 8 bya fastening device 9, arranged in one of the perforations of the upper bar 8 of the oblong frame. The upper arm 11 is yieldingly connected with the pitman 4 by means of two telescoping sections 14 and 15 and a spring 19 interposed between the end of one section and a perforated head of the other. The section 15 consists of a sleeve, which receives the adjacent end of the section or bar 14, and which has its outer end perforated to receive a fastening device forconnectingitwith the spring, such fastening device 12" passing through one of a series of perforations of the arm 11 at a point above the shaft and making the connection adjustable. The spring 19 is a spiral or coiled spring, and one end is secured in a perforation of the sleeve or tubular section 15, and its other end is arranged in a similar perforation of the head of the other section. The sections 14 and 15 of the yielding connection are adapted to telescope on each other, to yield to the varying distance between the spring and the pitman, the latter being provided with perforations 18, arranged at intervals at its upper end to provide an adjustable connection.

Then the crank 5 in its rotation reaches the point designated by the letter a, the upper portion of the spring will lie on the right or in front of the shaft 6 and will operate to draw the crank forward past the point a, the upper-dead-center. When the crank reaches the lower dead-center, the spring will be bowed minordetails of construction may be resorted to without departing from the principle or sacrificing any of the advantages of this invention.

lVhat I claim is 1. The combination with a treadle, a shaft having a crank, and a pitinan extending from the treadle to the crank, of a spring having itslowerend rigidly and-adjustably connected with the treadle, said spring extending upward in front and above the shaft, and yielding connections between the pitinan and the upper portion of the spring, said connections being adjustably and pivotally attached to the pitman and the spring, thepoint of attachment to the latter being above the shaft, substantially as described.

2. The combination with a treadie, a shaft having a crank, and a pittnan extending from the treadle to the crank, of an oblong frame mounted on one end of the treadle and hav ing upper and lower bars provided with perforations, a spring extending upward from the treadle in front and above the shaft and composed of a central resilient strip of metal and upper and lower arms provided with perforations, the lower arm being adjustably secured to the oblong frame by fastening devices passing through the perforations, and the yielding connection between the upper arm of the spring and the pitman comprising the telescoping sections having their outer terminals pivoted to the said spring and thepitman by fastening devices arranged in perforations of the same, and a spiral spring connecting the telescoping sections, substantially as described.

In testimony that I claim the foregoing as my own I have hereto aflixed my signature in the presence of two witnesses.

DAVID SEIBER'I, SR.

\Vltnesses:

E. O. BARNUM, I. B. WAcH'rnL. 

